The air frame structures of helicopters are subject to significant vibrations. These are caused, for example, by air flow along the surface of the helicopter. In the case of so-called tail-shake vibrations, the rear end of the helicopter vibrates both in the vertical as well as in the horizontal directions. In particular, the first natural bending characteristics in the vertical and horizontal directions are responsible for cabin vibrations at the seat of the pilot and they greatly influence these vibrations. In order to reduce tail-shake vibrations, vibration dampers are conventionally utilized. These vibration dampers are essentially comprised of weights and springs.
In the conventional vibration dampers, the problem exists that great additional weight is necessary which significantly increases the total weight of the helicopter. In addition, these dampers require substantial space for their installation which is not always available at the location where they provide an optimal damping action. In addition, expensive fastening devices are necessary for the springs and the weights at various places in the helicopter.